Precision Positioning Vibration Fiber System

With the increasing progress of science and technology, people pay more and more attention to the safety of major infrastructure, and the requirements for related safety monitoring technology are also getting higher and higher.

The distributed vibration optical fiber system (also known as the precision positioning vibration fiber system) can do distributed sensing of the external disturbances along the fiber, just like the human sensory nervous system can continuously monitor in all directions. It hairreplaceable advantages in accurate event positioning, concealment, environmental adaptability, etc., and it achieve notable results in the application in important core facilities and regional security monitoring.The distributed vibration optical fiber detection system takes thesensing cable as the sensing unit, and can carry out real-time and continuous monitoring through various vibrations caused by the vibrating optical fiber with directly touched or transmitted through the carrier (such as soil cover, barbed wire, fence, etc.), and can simultaneously locate multiple intrusion points. It has the characteristics of front-end passivity, long detection distance, lightning resistance, anti-interference, and follow-up concealed installation.To solve the problem that the whole route of routine inspection measures can not be mnitored in real time, and the accident can not be warned before the accident etc.It is widely used in oil and gas pipeline mining, civil aviation airport, judicial prison, petrochemical industry, rail transportation, military industry and other industries

(Vibrating optical fiber system)

Optical fiber sensing technology

Optical fiber sensing technology is a new type of sensing technology based on optical fiber developed in the mid-1970s, which is a new technology developed on the basis of optical communication technology ,optical information processing technology and electrical information processing technology. Optical fiber sensing technology makes optical fiber not only a carrier of information, but also a sensitive medium for sensing external signals. The optical fiber not only maintains the characteristics of high-speed transmission of information with a large capacity, but also has the sensing characteristics that sensitive sensing of subtle changes in various physical and chemical quantities through the modulation and processing of various parameters of light amplitude, phase, frequency and polarization state.

(Vibrating optical fiber system)

There are two main types of optical fiber vibration detectors for intrusion detection

There are defense area type and precision positioning type.

Defense area type is generally used in short-distance key places, such as schools, gas stations, oil depots, government units, etc., to display alarm areas by dividing defense areas. According to the application, each defense zone is 50-200 meters, and there are generally up to 16 defense zone type vibration fiber optic detectors. Precision positioning vibration detectors are generally used in ultra-long distance perimeter, such as border lines, oil pipelines, railway lines and other long-distance monitoring, can accurately locate the position, the maximum accuracy to plus or minus 2 meters. The maximum detection distance of a single device is 150KM.

System function

1. The electronic map of the system displays the distribution of the entire perimeter, and display intrusion information by dynamic real-time graphics (including: alarm location, alarm time, alarm type), which can deploy, withdraw and set alarm strategies for the defense area.

2. The system can realize alarm recording and alarm handling functions.

3. Real-time data view, can provide the real-time display function of the alarm policy value have set .Real-time calculation values in the alarm policy will be showed in time.

4. Alarm view function, open the alarm record view window, you can check the alarm records and broken cable alarm records in detail. Users can check according to the time range set and fortified area.Checking results can be output in text format.

5. Have multiple monitoring, remote access function. The system provides remote access to any computer in the LAN, and provides automatic deployment and withdraw function of designated defense area at designated time.

6. Provide a hierarchical user management mechanism.

7. The system has self-diagnosis function to quickly locate faults.

8. Provide linkage between interface with video system, which can realize automatic video screenshots and other functions.

System theory

The principle of the distributed vibration optical fiber monitoring system is that the laser module emits a series of lasers, which are divided into two paths after pass the coupler, one is the detection light and the other is the reference light. The detection light is pulsed and input into the optical fiber under test. The reflected signal light carries the relevant information of the optical fiber to be measured (vibration information generated by the outside world at a certain point of the optical fiber).And the reference light of the other way is used as the local light and is coherently coupled with the Rayleigh scattering echo through the local light. The coherent light enters the photoelectric detection module, and the signal after photoelectric conversion is collected and processed by the acquisition system. Finally, the energizer computer completes the display of time domain heartbeat waveform and frequency domain energy waveform, and realizes the related functions such as pattern recognition.

System features

◆ Multi-point recognition: there is no blind area in the whole monitoring range of the system, and multiple intrusion points can be located at the same time and up to 8000.

◆ The system has high sensitivity and can set the alarm threshold and type according to actual needs ,to realize real-time alarm;

◆ Accurate positioning: accurate location of the event, the highest accuracy can reach ±1 meter.

◆ Fixed point capture: with the camera, high positioning accuracy, can capture intruders at night.

◆ High reliability: The dual-channel optical fiber energizer is used to form a ring network, and the system can still work normally after the sensor cable is cut.

◆ One-key check: The system software automatically identifies the length of the sensing cable with one key, which is easy to check the broken point, easy to install and maintain, and does not require professional OTDR tools.

◆ Intelligent algorithm: The system adopts intelligent behavior detection algorithm and space filtering algorithm, which can eliminate all kinds of interference and vibration in the environment, effectively reduce false alarm, and improve the alarm accuracy. 

◆ Remote detection: single channel detection distance can reach 50km.

◆ Corrosion-resistant, can be used in long-term even buried in wet, underwater and other harsh environment.

Technological superiority

1.Passive, intrinsically safe

No power supply is required in the measured information area; Suitable for the protection monitoring of flammable, explosive and other dangerous goods , no other explosion-proof treatment needed ; Suitable for the protection monitoring

of high voltage condition ,Free from strong electromagnetic interference.

2.High sensitivity

The light signal can detect any small change of physical quantity and chemical quantity .

3.Strong environmental adaptability; Stable and efficient; cost-effective

Good weather resistance: corrosion resistance, high and low temperature resistance, can work in harsh chemical environment and field environment; Can achieve long distance, wide range of detection, cost-effective.

Perimeter prevention is the most basic system in public security prevention, is the first defense line to prevent illegal intrusion and abnormal events, but also a very important defense line. Although there is a dense surveillance camera and other alarm peripherals in the previous perimeter defense system, but monitoring personnel are often easily distracted when they face dozens or even hundreds of video monitoring points. For sudden intrusion and abnormal events, these systems can not accurately alarm positioning or timely release of alarm processing process, it’s easy to miss the best time to stop intrusion. That will turn the entire perimeter defense system into a video system for post-mortem evidence.

Distributed vibration optical fiber detection system with its fully distributed sensing, high sensitivity, anti-electromagnetic interference, good concealment, high positioning accuracy advantages, have been widely used in the long distance perimeter security, oil and gas pipeline safety monitoring, smart grid, railway safety monitoring and other fields , and received wide praise.